Hydraulic power transmissions



Jan. 22, 1957 Filed April 21, 1955 fay/0e L. W. CORNWALL HYDRAULIC POWER TRANSMISSIONS 5 Sheets-Sheet 1 IN VEN TOR.

1:0 W Ca e/M4444 Jan. 22, 1957 L. w. CORNWALL 2,778,244 HYDRAULIC POWER TRANSMISSIONS Filed April 21 1955 INVENTOR. L50 W: C ole/1444441.

Jan. 22, 1957 w. CORNWALL 2,778,244

HYDRAULIC POWER TRANSMISSIONS Filed April 21, 1955 s Sheets-Sheet a $4 6'9 O 6'9 (7\ O 45 O 6'6 b Press-we 6/00 we INVENTOR. C 0161/14/44;

Jan. 22, 1957 L. w. CORNWALL HYDRAULIC POWER TRANSMISSIONS 5 Sheets-Sheet 4 Filed April 21, 1955 INVENTOR. Cale/Wm 4 4rrae/vzv 1957 L. w. CORNWALL 2,778,244

HYDRAULIC POWER TRANSMISSIONS Filed April 21, 1955 5 Sheets-Sheet 5 IN V EN T 0R. 6064 14 44;

United States Patent 2,778,244 HYDRAULIC rowan TRANSIVHSSIONS Leo W. Cornwall, El Cajun, Calif. Application April 21, 1955, Serial No. 502,918 3 Claims. c1. 74-687) My invention relates to hydraulic power transmissions, particularly as a means for controlling the changing of speeds from zero to solid drive, forward or reverse, in any type of power driven machines, and its objects are to dispense with the complicated and expensive power transmissions now in common use and to replace the same with simple, economical and more effective mechanisms embodying my invention; to render the parts readily accessible for inspection, adjustment, replacement and repair, and in general to provide a power transmission which is simple and economical of construction, efficient in action and of prolonged life and durability. My invention further consists of other novel features of construction, and combinations and arrangements of parts illustrated in the drawing, and hereinafter more particularly described and claimed.

Attention is hereby directed to the accompanying drawing illustratin a preferred form of my invention, in which drawing similar numerals of designation refer to similar parts throughout the several views, and in Which- Fignre l is a vertical longitudinal sectional view of my power transmission, showing its connection with the shaft of an engine or other source of driving power;

Fig. 2 is a section on line 22 of Fig. 1, looking in the direction indicated by the arrows, and illustrating the torque plates and related parts;

Fig. 3 is an enlarged section of a detail of Fig. 2, looking downwardly in the direction indicated by the arrows Fig. 4 is a vertical cross section on line 4-4 of Fig. 1, looking in the direction indicated by the arrows, and showing the inner bank of the cylinder block for the variable capacity pump;

Fig. 5 is a vertical cross section on line 5-5 of Fig. 1, looking in the direction indicated by the arrows, and showing the outer bank of said cylinder block;

Fig. 6 is a vertical cross section on line 6-6, of Fig. 1, looking in the direction indicated by the arrows, and showing the inner face of the cylinder block of the fixed capacity motor and adjacent parts;

Fig. '7 is a vertical cross section on line '77 of Fig. 1, looking in the direction indicated by the arrows, and showing the central control rod and related parts;

Fig. 8 is a vertical cross section on line $8 of Fig. 1, looking in the direction indicated by the arrows, and showing the rotating valve plate, and a portion of the cylinder block of the fixed capacity motor;

Fig. 9 is a vertical cross section on line 99 of Fig. 1, looking in the direction indicated by the arrows, and showing the rotating valve plate, a portion of the fixed valve plate and related parts;

Fig. 10 is a vertical longitudinal section on line 1ill0 of Fig. 9, looking in the direction indicated by the arrows, and showing a piston, at the top of its stroke, of the outer banking cylinders of the variable capacity pump and related parts;

Fig. l l is a vertical longitudinal section on line 11l1 of Fig. 9, looking in the direction indicated by the arpump, and related parts;

Fig. 12 is an enlarged vertical section of a detail of: Fig. 1, showing the racks and pinion and related parts of the central control mechanism; and

Fig. 13 is a vertical cross section on line 13-13 of Fig. 12, looking in the direction indicated by the arrows,- and showing said racks, pinion and related parts.

Referring to the drawing, longitudinally extending from the engine 15 is the shaft 16, and slidably mounted upon said shaft is the collar 17, having the annular groove 18' engaging with the block 19, connected with the arms of' the conventional control yoke 20. Pivotally connected with the rim 21 of the collar 17, and diametrically opposite, are the inner ends of the links 22 (only one being shown), the outer ends of which are pivotally connected respectively with the bell cranks 23 (only one being shown) (see Figs. 1 and 2), each of which is pivotally mounted upon the outer torque plate 24, keyed to the shaft 25; such shaft being in longitudinal extension of the shaft 16, and telescopically connected therewith. Also pivotally mounted upon the torque plate 24 are the flat slotted rocker arms 26 (only one being shown), and the weighted governor arms 27 respectively connected with the slots of the arms 26.

Keyed to the shaft 16 is the inner torque plate 28, connected with the outer torque plate 24 by two helical compression springs S mounted therebetween lugs integral with said torque plates; said springs serving to hold said torque plates in unturned relation under normal operating conditions, but allowing said plates to be turned in close edge relation upon the compression of said springs brought about through excessive torque of the shaft 16.

Integral with the inner torque plate 28 and located diametrically opposite upon cut-out portions near the edge thereof are the cams 29 (see Figs. 1 and 2) which, in the event of excessive torque of plate 28, are brought into contact with the rocker arms 26 respectively and serve to retard the movement thereof (see Figs. 2 and 3).

Formed in each of the rocker arms 26 is an arcuate slot 30, and sliding within said slot in each case is a pin 31 secured to one end of one of the links 32, each of which is pivotally connected with the collar 33, said collar being slidable upon shaft 25. Also pivotally connected with the collar 33 are the links 34 (only one shown) kept in parallel relation by links 35 (only one shown) pivotally connected to said links; and each of the links 35 is provided with a horizontally extending slot within which slots slide the pins 36 (only one being shown), afiixed to the bell-crank 23 (see Fig. 1).

Integral with the outer end of the shaft 25 is the cylindrical head 25a, having formed in the central portion thereof, the cylindrical recess 25b. Extending through the rim 250 of said head in openings provided therefor, are the bolts 33, the threaded ends of which engage with threaded openings in the collar 41, and serve to hold the said head and collar in close abutting engagement. Within the central portion of the collar 41 and in alignment with the recess 25b in the cylindrical recess 41a. Keyed to the collar 41 is the shaft 45, in longitudinal alignment with shafts 16 and 25, and also in extension thereof and in alignment with said shafts is the shaft 65, as hereinafter more particularly set forth.

Secured by pins to the collar 33, are the two bolts 37, in threaded connection with the discs 39 and 40, slidable within the recesses 25b and 41a the axes of which discs are aligned with the axes of shafts 16 and 25 as shown in the drawing (see Figs. 1 and 7). As a result of this arrangement of parts, the automatic controlling mechanism is enabled to move the control rod 44 back and Patented Jan. 22, 1957 forth longitudinally, the head of which rod closely engages with a recess formed in the disc 40 between said discs.

Journa-lled within bearings 42 and. 43, andmpunted upon a supportingstructure, are the hubs 46a and 48a,

respectively, of the end plates 46 and 481 of the cylin drical housing 47 of my power transmission. Keyed to the wall of said housing, within the hollow thereof, are the cylinder block 55 of thevariable capacity pump, the fixed cylindrical valve plate 57, and the cylinder block 60 of the fixed capacity motors (see Figs. 1, 4, 5, 6, 10 and 11 Deeply milled within the shaft 45, and extending longitudinally thereof is the slot 45a, and shaped to engage therewith and to slide therein is the L-shaped rack 51, secured to the threaded end of the control rod 44. Extending laterally through the walls of the slot 45a, and at. right. angles thereto are openings, therein, within which is. journalled two portions of the pinion 54, the central portion meshing with rack 51, and the ends of said pinion proiecting beyond the shaft 45 engage with the racks 3 upon'plates 50. The said plates are mounted to slide within shallow recesses formed within the circular plates 49, keyed to the shaft 45, and rotate therewith, and said plates sliding back and forth at 90 with said shaft (see Figs. 1, 4, 5, 12 and 13).

Protruding from the said plates 50 are segmental projections on the faces of which are cut the racks 53, the said projections being separated by the elongated slots 53a extending therethrough. Secured by rivets to the plates 50 and projecting therefrom are the rings 52 encompassing the peripheral edges of the. racks 53.. As shown in Fig. 13, each of the mounting units there shown comprises the circular plate 49, the rectangular plate 50, the rack projection 53, and the ring 52; the said units being normally in eccentric position relative to shaft 45, but being subject to being moved to concentric position in accordance with the action of rod 44, as hereinafter described (see Figs. 12 and 13).

Referring to Figs. 4 and 5, illustrating the cylinder block 55, there is shown the radial arrangement of the cylinders 55a and pistons 56, the inner ends of said pistons being in sliding contact with the periphery of ring 52, said cylinders having the usual outlet and inlet ports 68 and 69 and said pistons being operated in accordance with the rotation of said ring, as will be readily understood by those skilled in the art. Preferably, to insure contact of the pistons 56 with the rings 52, I insert within the cylinders 55a and in the spaces between the heads of the piston and plugs screwed into the heads of the cylinders,

the helical compression springs 79 (see Figs. 4 and 5). As shown in Figs. 1, l0 and 11, there is keyed to the housing 47, and firmly secured to said cylinder block, the port ring 57 having passageways therethrough positioned to register constantly with the outlet and inlet ports of the cylinders of said block. Keyed to the shaft 45 and rotating therewith is the cam 59, slidably and mounted upon said cam is the rotating valve plate 58, provided with the arcuate slots 70 and 71, located to make movable registration with the passageways 66 and 67 in the port ring 57 (see Figs. 1, 8-11).

Contacting the end plate 48, and keyed as aforesaid to and within the housing 47, is the cylinder block 60, within the hollow of which near the periphery of which diametrically opposite are formed the two cylindrical recesses within which are conventionally installed the fixed capacity motors 61.

Integral with said cylinder block 60, and constituting the inner side thereof is the wall 6011, having formed therein the two annular grooves 72 and 73, and leading from these grooves through the said wall to the fixed capacity motors 61 are the ports 74 and 75; the said grooves being located to make continuous registration with ports 70 and 71 in valve plate 53 (see Figs. 1, 6, 8-1;);

Keyed to the outer end of the shaft 45, is the bevel gear62', "meshih'g with th'e'two bevel gears 64, mounted upon the shafts of the motors 61. Also meshing with the gears 64 is the bevel gear 63 keyed to the shaft 65, being in extension of shafts 16, 25 and 45; and being telescopically connected with the shaft 45, and slidably rotatable thereon.

As shown in Fig. 1, seals 76-are provided adjacent to the shaftsflfi and 6,5 within annular grooves provided therefor, for sealing olf the end plates 46 and 48 so as to prevent leakage of oil from the housing 47, helical compression springs 77 being supplied within said. grooves, and serving t'okeep said seals in proper contact with the adjacent parts, and to take up possible expansion of heated oil.

For oil replacement, a pipe plug 78 closing a. port provided therefor through the wall of the housing 47 or other conyentional means, may be supplied for such purpose.

In the operation of the apparatus hereinbefore described, starting from static position, at which time the several parts therein contained is completely filled with oil'and sealed from leakage therefrom, and also sealed from the admission of air therein, the capacity of the variable capacity pump is exactly equal to the capacity of the fixed capacity motors 61, and the links 32 are in horizontal emplacement B as shown in dashed lines in Fig. l; the engine 15 is started causing the rotation of the shaft 16, the shafts 25 and 45 in extension thereof; and all parts in connection with said shafts. At the same time, the housing 47 i and connected parts are caused to rotate at exactly one-half of the speed of the engine, except the shaft 65 and gear 63 are stationary at that time and in idle relation with the shaft 45. Also at this time, all of the pumps and motors above referred to are running at one half speed of the engine, and the speed of the. flow of the oil through the passageways of the valve plates 57 and 58 would be one-half of conventional pumps and motorsas now used in the art.

Thereupon, through manual manipulation of the yoke 20, the collar 17 is slid upon the shaft 16 toward the engine 15, causing the inner ends of the links 32 to spread outwardly to take the position A, shown in Fig. l, the governors 27 retaining their normal position, while the. engine is in an idling position. Then, upon the engine being speeded up, the said governors are by reason of increased centrifugal force, thrown outwardly, thereby causing the links 32 to be pulled inwardly together with i connected parts as hereinbefore set forth, and causing the reduction to concentric equilibrium of the rotation of the rings 52 heretofore in eccentric relation to shaft 45 as above described.

Taking, for example, the capacity of the fixed capacity pump and the variable capacity pump at ten gallons per minute at idling speed, then upon acceleration of the capacity of the variable capacity pump is reduced in accordance with the degree of acceleration from ten gallons to zero, or complete cessation of the flow of pil through said variable capacity pump, to the fixed capacity pumps. As the result of the said reduction of the flow of oil to the fixed capacity pumps, these motors are forced to slow down and through connections with the bevel gears 64, being in constant mesh with bevel gear 63, forces the shaft 65 to rotate in the same direction as the coinbined shafts 16, 25 and 45, the rate of rotation of the shaft'65 gradually rising to the rate of rotation of saidv combined shafts, in direct proportion to the amount of oil'being supplied to motors 61 from the variable capacity pump, until the rings 52 are brought from eccentric to'fconcent'ric relation to shaft 45 as hereinbefore 'set forth? 'at which time the speed of rotation of the housing 47hfas caught up with the speed of rotation of said shafts, andthe'shaft 65 caused to rotate at the same speed, the flow of oil having completely stoppedand all of said shafts and housing are rotating as a singleunit. In the event of excessive torque of the shaft 16, the springs are compressed and the plates 24 and 28 are brought into close edge relation, thereby retarding the movement of the rocker arms 26 as above described.

In the operation of the apparatus having returned to idling position, the reversal of rotation of shaft 65 is accomplished through manual manipulation of the yoke 20 so as to move links 32 down into position C, as indicated in dashed lines in Fig. 1. Then upon the engine being speeded up, the governors on arms 27 are, by reason of increased centrifugal force, thrown outwardly, thereby causing the links 32 to be pushed outwardly, together with connected parts, and causing an increase of eccentricity of rotation of rings 52; and as a result the flow of oil from the variable capacity motor is increased, forcing an increased rotation of pump 61, and through gear connections 62, 63 and 64, the rotation of shaft 65 is reversed.

My invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments, as above set forth, are therefore to be considered in all respects as illustrative and not restrictive, the scope of my invention being indicated by the appended claims rather than by the foregoing description, and all changes which may come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What I claim and desire to secure by Letters Patent is:

1. A hydraulic power transmission, comprising a driving shaft and means for rotating said shaft; a driven shaft connected with and in alignment with said driving shaft and means for varying the rotation thereof relative thereto; a closed housing filled with lubricating oil and connected to said driving shaft and rotating therewith; a variable capacity pump mounted within said housing and means operatively connecting the same with said driving shaft and saiddriven shaft; a plurality of fixed capacity motors and a gear train operatively connecting the same with said driving shaft and said driven shaft; means co operating with said means for causing, controlling, and terminating the flow of oil from said variable capacity pump to said fixed capacity motors, and means for connecting and disconnecting said driven shaft with and from said driving shaft in accordance with said flow of oil.

2. The subject matter of claim 1, including a valve plate mounted to rotate within said housing and located between said motors and provided with passageways for the flow of oil to and from said variable capacity pump.

3. The subject matter of claim 1, each of said fixed capacity motors comprising a recessed cylinder block secured to said housing, and each of the shafts of said motors being operatively connected by a diiferential gear train to the driving shaft and the driven shaft.

References Cited in the file of this patent UNITED STATES PATENTS 2,639,629 Wiser May 26, 1953 2,692,513 Hattan Oct. 26, 1954 FOREIGN PATENTS 9,519 Great Britain of 1911 769,193 Great Britain Feb. 24, 1934 

